Brunswick Layover Environmental Assessment (EA)

Appendix D: Air Quality Assessment

September 2013

BRUNSWICK RAIL 

MAINTENANCE FACILITY 

POTENTIAL AIR QUALITY IMPACTS OF 

PROPOSED FACILITY ON NEARBY 

SENSITIVE LAND USES 

Parsons Brinckerhoff 

August 2011 
PARSONS 

BRINCKERHOFF PAGE 2 

Introduction 

The proposed Brunswick layover facility would service and store rail cars and locomotives. Primarily, the 

facility would store up to three trains in a heated space so that the locomotive engines could shut down 

at night during cold weather periods. Locomotive emissions, therefore, would be generated within the 

facility mostly during locomotive start-up periods in the morning and while idling for restocking and 

cleaning during brief visits during the day. 

The proposed facility would be located near tracks that are being used by existing commuter and freight 

trains. Emission sources from the proposed facility would include: 

· Six (three round-trip) commuter trains passing the site each day; 

· One to two freight trains passing the site each day; 

· Up to three commuter trains stored overnight within the proposed layover/maintenance building; 

· Up to three commuter trains at the facility during the day for cleaning and restocking; and 

· The HVAC system of the layover/maintenance building, which will to maintain the temperature inside 

the facility overnight at approximately 45 degree Fahrenheit. 

A conservative (screening-level) air quality analysis was conducted, using the facility’s schematic layout 

and the distance to nearby sensitive land uses, to estimate the potential air quality impacts of these 

emissions. 

Pollutants of Concern 

Criteria pollutants (i.e. pollutants for which national ambient air quality standards [NAAQS] have been 

established) and non-criteria toxic air contaminants (TACs) for which health risk values were developed 

by the U.S. Environmental Protection Agency (EPA) were considered in this analysis of potential localized 

impacts. The criteria pollutants considered are: 

· Nitrogen dioxide (NO2) from the diesel locomotives and the gas-fired HVAC system, and 

· Particulate matter smaller than 10 microns (PM10) and particulate matter smaller than 2.5 microns 

(PM2.5) from diesel locomotives. 

There are also a number of toxic pollutants (with various toxicities) that are either carcinogenic or noncarcinogenic that can potentially be released from diesel engine locomotive exhaust or stack (vents) of 

the gas-fired HVAC system of the maintenance building. These pollutants have the potential to cause 

cancer and other adverse health problems, including respiratory illnesses, and increased risk of heart 

disease. 

Analysis of the representative TAC’s were therefore conducted that considered both (long-term) 

carcinogenic and chronic non-carcinogenic and acute (short-term) health risks. For these analyses, PM10

emission factors were used to represent diesel PM. 

Emission Factors and Rates 

Emissions factors from the locomotives were estimated as follows: 

· Diesel particulate matter (PM10), PM2.5, and NO2 emissions from locomotives were estimated 

assuming emission standards applicable for old locomotives (i.e., manufactured before 2002), EPA 

Locomotive Emission Standards, Regulatory Support Document, 1998, Table 4-9, and locomotive 
PARSONS 

BRINCKERHOFF PAGE 3 

emission rates were estimated based on a GE7FDL locomotive model, and appropriate notch settings, 

activity times, and idling durations; 

· Emissions from the HVAC system of the maintenance building were estimated using EPA’s 

“Compilation of Air Pollutant Emission Factors” (AP-42) emission factors for a natural gas system; 

· TAC emitted from locomotive diesel engines were estimated using EPA AP-42 emission factors for 

speciated organic compounds for large stationary uncontrolled diesel-fuel engines (Table 3.4.-1 and 

3.4.-3). 

· TAC emitted from the HVAC system were estimated using EPA AP-42 emission factors for speciated 

organic compounds from natural gas combustion (Table 1.4.-3). 

Emission rates for the locomotives were estimated based on the following layover facility operating 

scenario, which was supplied by the project’s design engineers: 

· Three trains would arrive in the evening, be stored overnight in the maintenance facility and 

depart in the morning; 

· During the day, three trains would spend about 30 minutes idling within the facility for cleaning 

and restocking; 

· One freight train a day travel would travel through the project area on the existing extended 

siding and one train every two days would travel by the project area on the new siding; 

· The commuter trains, which are assumed to be 3,200 horse-power (hp) each, would idle for 30 

minutes inside the building and will be moving in the project area for approximately 30 minutes 

over a 24-hr period (with the locomotive engines going through all notches [gears]) (Table 1); 

and 

· The freight trains, which are assumed to be 4,200 hp each, would be moving in the project area 

for approximately 30 minutes over a 24-hr period (with the locomotive engines going through all 

notches [gears] (Table 2). 

Emission rates for all applicable pollutants, together with the parameters used for the analyses, are 

provided in Table 3 thru 5. 
PARSONS 

BRINCKERHOFF PAGE 4 Table 1 Commuter Locomotive Horse-Power and Load Factors Notch HP (1) % HP in use Percent Time in Notch (2) Actual % time in use Engine HP (3) Equivalent HP Used in Analysis Load Factors (4) Idle 13 0.3% 47% 100% 11 11 0.3% Dynamic Brake 128 3.4% 6.2% 11.8% 109 13 1 211 5.6% 7.0% 13.3% 179 24 2 457 12.1% 5.1% 9.7% 388 38 3 928 24.6% 5.7% 10.8% 787 85 4 1,084 28.7% 4.7% 8.9% 919 82 5 1,666 44.2% 4.0% 7.6% 1413 107 6 2,375 62.9% 2.9% 5.5% 2014 111 7 3,182 84.3% 1.4% 2.7% 2699 72 8 3,773 100.0% 15.6% 29.7% 3,200 949 Total for Moving Locomotive 100% 100% 1,492 47% Assumptions: 1. Notch horsepower usage was obtained from tests conducted by Motive Power Company. 2. Percent time in each notch is based on EPA-estimated high power duty-cycles for locomotives. 3. Each commuter train locomotive is assumed to be 3,200 hp. 4. Average load factors were estimated for two operational modes: idling and moving. It is assumed that the engines go through all notches when moving.
PARSONS 

BRINCKERHOFF PAGE 5 Table 2 Freight Locomotive Horse-Power and Load Factors Notch HP (1) % HP in use Percent Time in Notch (2) Actual % time in use Engine HP (3) Equivalent HP Used in Analysis Load Factors (4) Idle 13 0.3% 59.8% 100% 14 14 0.3% Dynamic Brake 128 3.4% 0.0% 0.0% 142 0 1 211 5.6% 12.4% 30.8% 235 72 2 457 12.1% 12.3% 30.6% 509 156 3 928 24.6% 5.8% 14.4% 1033 149 4 1084 28.7% 3.6% 9.0% 1207 108 5 1666 44.2% 3.6% 9.0% 1855 166 6 2375 62.9% 1.5% 3.7% 2644 99 7 3182 84.3% 0.2% 0.5% 3542 18 8 3773 100.0% 0.8% 2.0% 4,200 84 Total for Moving Locomotive 100% 100% 866 21% Assumptions: 1. Notch horsepower usage was obtained from tests conducted by Motive Power Company. 2. Percent time in each notch is based on EPA-estimated high power duty-cycles for locomotives. 3. Each freight train locomotive is assumed to be 4,200 hp. 4. Average load factors were estimated for two operational modes: idling and moving. It is assumed that the engines go through all notches when moving.
PARSONS 

BRINCKERHOFF PAGE 6 

Table

3

P

M10 Emis

sion Rate

s for C

o

m

m

uter and Freight Lo

c

o

m

otiv

e

s

Table

4

P

M2.5 Emis

sion Rate

s for C

o

m

m

uter and Freight Lo

c

o

m

otiv

e

s

1. P

M2.5 emissions are assumed to be 9

2%

of the P

M10 emissions

HMF Operations Mode

Average

Number of

Locomotives

Engine

Horsepower

(hp)

Load

Factor

(%)

Tier 0

Emission

Factors

(g/bhphr)

PM10

Emission Rates

24-

hour Annual

g/sec lb/year

Brunswick Mainline TruckC

o

m

muter Trains

Idle 5

3,2

00

0.3%

0.3

2 1.0

2E04

8.3

9E0

5

Moving 6

3,2

00

47%

0.3

2 1.6

6E02

1.3

6E0

2

Brunswick Exist. &

New

Siding Freight Trains

Idle 1.5

4,2

00

0.3%

0.3

2

8.0

4E05

6.61E0

5

Moving 1.5

4,2

00

21%

0.3

2

2.4

0E03

1.98E0

3

Total Train Emissions 1.9

2E0

2

1.5

8E0

2

HMF Operations Mode

Average

Number of

Locomotives

Engine

Horsepower

(hp)

Load

Factor

(%)

Tier 0

Emission

Factors

(g/bhphr)

PM2.5

(1)

Emission Rates

24-

hour Annual

g/sec lb/year

Brunswick Mainline TruckC

o

m

muter Trains

Idle 5

3,2

00

0.3%

0.3

2 9.39E05

7.72E05 Moving 6

3,2

00

47%

0.3

2 1.53E02

1.25E02

Brunswick Exist. &

New

Siding Freight Trains

Idle

1.5

4,2

00

0.3%

0.3

2

7.40E05

6.08E05

Moving 1.5

4,2

00

21%

0.3

2 2.21E03

1.98E03

Total Train Emissions 1.76E02

1.47

E02
PARSONS 

BRINCKERHOFF PAGE 7 Table 5 NO2 Emission Rates for Commuter and Freight Locomotives HMF Operations Mode Average Number of Locomotives Engine Horsepower (hp) Load Factor (%) Tier 0 Emission Factors (g/bhp- hr) NO2 Emission Rates 24-hour Annual g/sec lb/year Brunswick Mainline Truck Commuter Trains Idle 5 3,200 0.3% 8.6 2.74E-03 2.26E- 03 Moving 6 3,200 47% 8.6 4.46E-01 3.66E- 01 Brunswick Exist. & New Siding Freight Trains Idle 1.5 4,200 0.3% 8.6 1.24E+00 1.78E- 03 Moving 1.5 4,200 21% 8.6 6.46E-02 5.31E- 02 Total Train Emissions 1.76E+00 4.23E- 01
PARSONS 

BRINCKERHOFF PAGE 8 

Dispersion Modeling 

As the operation of the layover facility has the potential to cause health impacts on nearby sensitive land 

uses due to emissions from the locomotives and HVAC system, a conservative (preliminary) dispersion 

modeling analysis was conducted. EPA’s AERMOD atmospheric dispersion model was used to simulate 

physical conditions and predict pollutant concentrations at nearby receptor locations. 

AERMOD is generally applied to estimate impacts from simple point-source emissions from stacks, as well 

as emissions from volume and area sources. The model accepts actual hourly meteorological 

observations and directly estimates hourly and average concentrations for various time periods. 

Regulatory default options and the rural dispersion algorithm of the AERMOD model were conservatively 

used in the analysis. 

A Cartesian grid network was developed around the facility that includes the rail tracks and the 

maintenance building. Based on a sketch of the prototypical facility, the closest sensitive land uses are 

approximately 175 feet from the existing mainline track. Therefore, the first row in Cartesian grid was 

placed at 175 feet south from the facility. However, the maximum concentrations found at 175 feet (or 

more) from the facility in any direction were used to estimate facility maximum potential impacts. These 

values were then added to estimated background values for the project area, and total concentrations 

compared with applicable federal air quality standards and health-related guideline values. 

Emissions from locomotive train operations were simulated as area sources and emissions from the 

maintenance building’s HVAC system were simulated as a point source. An emissions release height was 

assumed to be 3.6 meters (12) to approximate the height of the locomotive exhaust, and 10 meters (33 

feet) to approximate the height of the maintenance building. Meteorological data from Boston Logan 

Airport were used for analysis. 

Health Risk 

The maximum estimated concentrations of representative TACs were used to calculate cumulative cancer 

risks, chronic noncancer and acute hazard indexes associated with layover facility operations. 

Cancer Risk

From the multiple pollutants that may be emitted from locomotive diesel vehicular exhaust and gas-fired 

HVAC system operations, three pollutants are considered by EPA as carcinogens for which cancer unit risk 

factors were developed. These are benzene, acetaldehyde, and formaldehyde. The maximum individual 

cancer risk for each pollutant and total incremental cancer risks associated with these pollutants releases 

were calculated. Metal elements bounded to PM from natural gas combustion, such as arsenic, cadmium, 

nickel, and others, were considered as part of the PM10. 

The cancer risk calculation procedure, methodology and equations were based on the EPA Human Health 

Risk Assessment Protocol (HHRAP, Appendix B, Tables B-5-1 and C-2-1), together with EPA approved 

health values for cancer risk assessments. 

Chronic Noncancer Hazard Index 

Pollutants considered are those for which non-cancer RfC (reference dose concentration) guideline 

values, including diesel PM, are available from EPA’s Integrated Risk Information System (IRIS) or 

Prioritized Chronic Dose-Response Values for Screening Risk Assessments (EPA, Table 1, June 2007). 
PARSONS 

BRINCKERHOFF PAGE 9 

Calculations of chronic noncancer hazard index were based on the HHRAP, Appendix B, Tables C-2-1 and 

C-2-2) methodology and equations. 

Acute Hazard Index 

Acute hazard index analysis was based on HHRAP methodology and equations (HHRAP Appendix C, Table 

C-4-1 and B Table B-6-1). 

Results 

Criteria Pollutants 

Total estimated concentrations of the criteria pollutants are provided in Table 6. As shown, layover facility 

emissions of the criteria pollutants would not cause an exceedance of an NAAQS. 

Table 6 

Total Estimated Concentration of the Criteria Pollutants 

Pollutant 

Time 

Period 

NAAQS 

(ug/m3) 

Estimated 

Impacts 

(ug/m3) 

Background 

Conc. 

(ug/m3)* 

Total 

Estimated 

Concentrations

(ug/m3) 

Exceed 

NAAQS? 

NO2 Annual 100 23.4 22.6 46 No 

PM10 24-hr 150 4.0 56.0 60 No 

PM2.5

24-hr 35 3.8 20.2 24 No 

Annual 15 0.8 10.42 11 No 

*These are the highest values recorded at any of the State’s ambient monitors in Portland Maine in 2008. 

Toxic Pollutants 

Chronic Noncancer Risk 

As shown in Table 7, the total chronic noncancer hazard index (HI) found at a distance of 175 feet or 

more from the facility (0.0072) is less than 1. As such, potential chronic noncancer risks associated with 

layover facility operations are not considered to be significant. 

Cancer Risks 

Incremental cancer risks (dCR) were estimated using the maximum concentrations found at the 175 feet 

or more from the facility. Based on the results of this analysis (Table 7), it was determined that the 

overall incremental cancer impacts from all pollutants combined (5.2E-08) would be below the applicable 

significant threshold of one in-one million (1E-06), and, therefore, is not considered to be significant. 

Acute Risk 

As shown in Table 8, the total acute hazard index (AI) found at the 175 feet or more from the facility 

(0.078) is less than 1. As such, potential acute health risks associated with layover facility operations are 

not considered to be significant 
PARSONS 

BRINCKERHOFF PAGE 10 Table 7 Cancer Risk and Non-Cancer Hazard Index Results CAS Annual Exposure Concentration (EC) No. Contaminant No. Conc. (Ca) Carcinogen Non-Carcinogen URF dCR RfC HQ ug/m3 ug/m3 ug/m3 (ug/m3)-1 mg/m3 1 Acrolein 107-02-8 0.00013 1.28E-04 2.0E-05 6.39E-03 2 Formaldehyde 50-00-0 0.00174 7.15E-04 1.67E-03 1.30E-05 9.29E-09 9.8E-03 1.70E-04 3 Acetaldehyde 75-07-0 0.00043 1.75E-04 4.09E-04 2.20E-06 3.85E-10 9.0E-03 4.54E-05 4 Benzene 71-43-2 0.01310 5.38E-03 1.26E-02 7.80E-06 4.20E-08 3.0E-02 4.19E-04 5 Xylene 1330-20-7 0.00327 3.13E-03 1.0E-01 3.13E-05 6 Toluene 108-88-3 0.00475 4.56E-03 5.0E+00 9.12E-07 7 Diesel PM (PM10) 8.77E-01 8.41E-01 5.0E+00 1.68E-04 Cumulative Cancer Risk 5.2E-08 EPA Cancer Risk Threshold 1E-06 Total Hazard Index (HI) 7.2E-03 Hazard Index Threshold 1 Calculations described on the following page.
PARSONS 

BRINCKERHOFF PAGE 11 

Cancer Risk (dCR) and Non-Cancer Hazard Quotient (HQ) Calculations 

All calculations of inhalation cancer risk and hazard quotients are based on the EPA's Human Health Risk Assessment 

Protocol (HHRAP) methodology and equations. 

Ca values are based on the equation presented in HHRAP (Table B-5-1) using compound-specific emission rates 

Ca annual concentration estimated by the AERMOD model, ug/m3 

EC exposure concentration, ug/m3 (HHRAP, Appendix B, Table C-2-1) 

EC = Ca x EF x ED/AT x 365 days/year or EC = Ca x Fc, where 

EF exposure frequency, days/year, assumed by EPA to be equal 350 days/year 

ED exposure duration; Reasonable maximum exposure duration by EPA (RME) for Adult Resident = 30 years 

AT averaging time, years; AT is assumed by EPA to be equal 70 years 

Fc Fc = EF x ED/AT x 365 = 0.410958 

dCR individual lifetime cancer risk through direct inhalation of carcinogen 

dCR = EC x URF (HHRAP, Appendix C, Table C-2-1), where 

URF Inhalation unit risk factor, (ug/m3)-1. Source: EPA Integrated Risk Information System (IRIS) 

Non-Cancer Hazard Quotients 

EC exposure concentration, ug/m3 (the same equation for EC, as above, except that ED=AT=30 years) 

EC = Ca x Fnc, where 

Fnc Fnc = 0.958904 (EF x ED/AT x 365) 

RfC reference concentration, mg/m3. Source: EPA Integrated Risk Information System (IRIS) 

HQ hazard quotient for direct inhalation of non-carcinogen 

HQ = EC x 0.001/RfC (HHRAP, Appendix C, Table C-2-2) 

0.001 units conversion factor, mg/ug 
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BRINCKERHOFF PAGE 12 

Table 8 

Acute Hazard Index Results (AI)

 Acute Acute 

 CAS 

1-hr 

Conc. 

Exposure

 Criteria Quotients 

No. Contaminant No. (Cacute) (AIEC) (AHQ) 

 ug/m3 mg/m3 

1 Acrolein 107-02-8 0.01440 1.9E-04 7.6E-02 

2 Formaldehyde 50-00-0 0.14358 9.4E-02 1.5E-03 

3 Acetaldehyde 75-07-1 0.04620 8.1E+01 5.7E-07 

4 Benzene 71-43-2 1.42002 1.3E+00 1.1E-03 

5 Xylene 50-00-0 0.35400 2.2E+01 1.6E-05 

6 Toluene 50-00-0 0.51500 3.7E+01 1.4E-05 

Total Acute Hazard Index 7.8E-02 

Acute Hazard Index Threshold 1 

Potential Health Effects from Acute Exposure 

All calculations of acute hazard quotients are based on the EPA's Human Health Risk Assessment Protocol (HHRAP) 

methodology and equations. 

Cacute 1-hr concentration estimated by the AERMOD, ug/m3 

Cacute values are based on the equation presented in HHRAP (Table B-6-1) using compound-specific emission rates 

AIEC acute inhalation exposure criteria, mg/m3 

AHQ acute hazard quotient, unitless 

AHQ = Cacute x 0.001/AIEC (HHRAP, Appendix C, Table C-4-1) 

0.001 units conversion factor, mg/ug 
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BRINCKERHOFF PAGE 13 

Conclusions 

The result of these analyses are that the potential air quality impacts associated with emissions of the 

criteria and toxic pollutants releases from DBMSF operations are the following: 

1. Maximum estimated criteria pollutant concentrations at nearby sensitive land uses are within (do 

not exceed) the NAAQS and, as such, project impacts are not considered to be significant; 

2. The total chronic noncancer hazard index is less than threshold value of 1 and, therefore, is not 

considered to be significant; 

3. The total acute hazard index is less than the threshold value of 1 and, therefore, is not 

considered to be significant; and 

4. Total incremental cancer risk found is less than 1 per million and, therefore, is not considered to 

be significant.